CD4 and infection: Interestingly, when iDCs were first exposed to viral particles and 24 hours later put in presence of PAMPs like zymosan or PGN-SAndi, the same up-regulatory effect on DC-mediated cis-infection of CD4+ T cells by X4 virions was seen (Figure S3), thus confirming that treatment of iDCs with some PAMPs is enough to reduce the limiting effect exerted by restriction factors.